Die-casting machine.



' L. M. PARKHURST.

DIE CASTING MGHINB. APPLmATmNnLm JAN. ze, 1912.

`Patented Mar. 4, 1913.

. mf)- I-' WITNESSES.

A TTORNE Y.

ENTTED sTATEs EATENT oEErcE.

LAYTON M. PARKHURST, OF INDIANAPOLIS, INDIANA, ASSIGNOR ,'lfO THEINDIANA DIE CASTING DEVELOPMENT COMPANY, A CORPORATION 0F INDIANA.;

DIE-CASTING MACHINE.

Specification of Letters Patent. i

do hereby declare t-hat the following is a full, clear and exactdescription thereof,

reference being had to the accompanying drawings.

The object of this invention is to improve the Construction andoperation of stationary die Cast-ing machines whereby the manufacture ofcastings from certain metals will be facilitated and their quality,particularly theirl density, be improved. y

The chief feature of the invention consists in utilizing the products ofCombustion for forcing the molten metal out of the Crucible into thedie. It is accomplished by reversing the movement of the products ofCombustion by introducing compressed air into the exhaust passageway farenough away from the Crucible so that the pressure of the air will forcetheproducts of Combustion backward under sufficient pressure to forceout the molten metal and keep the air entirely out of Contact with themetal. Also a floating plunger plate rides loosely upon the metal .inthe Crucible and around the outlet pipe therein. The foregoing not onlyfacilitates the operation of such a device, but it enables the useof'compressed air or the like for causing the discharge of the metalinto the mold without said air or the .like coming into Contact with'themolten metal. This prevents oxidation and other disadvantages resultingfrom an outer contact of the air or the like with the molten metal. Italso simplies. the construction and mode Aof operation of the mechanism.

The nature -of the invention will be understood from the accompanyingdrawings andv v line 2+2 of Fig. 1. Fig. 3 is thedisk plunger shown inperspective.

In detail there is shown a semi-spherical melting oven 10 ixedlysupported by the arms 11 on triangular end frames 12 which are held inplace by Cross bars 13. The sort of frames whereby the melting oven 10is secured rigid inplace is immaterial to the invention. The oven isopen at the top 'and provided with a slightly beveled mouth 14 so thatthe top 15 can wedge vdownA ito place and fit tightly. The top 15 has acentrally located outletopening 16 for the molten metal, the lower partof said opening being threaded to receive a tube 17 which extendsdownward and the upper part of the opening 16 is surrounded by anannular projection 18 which surroundsa projection 19 on the lower part2O of the die whereby the die is centered and held in place. The uppermember 21 of the die is held in place beneath the lower end .of a screw23 which screws through a frame 24 and is turned by a wheel 25. In thismanner the die is held upon the top 15 and outlet 16 from the .Cruciblevand after releasing, the screw 23 may be removed. The die may be of theusual Construction.

The melting oven 10 is provided with suitable fire clay lining 26 andwithin said oven there is a Crucible 27 having an oval bottomV The tube17 projects down near the bot-torri o f the Crucible and below thewider'po'rtio thereof which is of the same diameter as the plunger sothat 'said disk plslnger"` vcannot move so low in the Crucible as toescape' from the outlet tube 17. The Crucible extendsu'p within theproximity of 'the -to 15, but 'a space 30 is left between said "p and'the' Crucible for the passage of Compressed air or gas from the oveninto the upper end of the Crucible. maintained heated by gaseous fuelComing in through a pipe 31 which is supplied with gas through a pipe 32and air through a pipe 33. A valve 34 Controls the 'air anda valve 35Controls thegas and the mixture. The fuel pipe 31 enters the melting-oven on one side of the Crucible and there is an exhaust port at 40from said .oven at the other side of the Crucible through a pipe 41.There is a compressed air pipe 42 Connected with the lair exhaust pipeand having a threeway valve 43 arranged so that when the valve is in onepositionz the exhaust will Patented Mar. a, wie; Application/filedJanuary 26, 1912. Serial'No. 673,628. I

The metal in the Crucible is the outer portion of the pipe 41 and openlcommunication between pipes 41 and 42 and then the compressedair willrush in from the pipe 42 through the pipe 41. There is a check valve 44in the fuel pipe 31.

The operation is as follows: The crucible is filled with molten metaland then the disk plunger 28 is placed therein and the top put in placewith the outlet tube 17 projectlng centrally through the plunger disk,28. l 'lhe mold is moved down into a tight fit and the fuel turned intothe heating chamber. This heats or maintains the heat of the'moltenmetal in the crucible and the heated gases` cannot reach the moltenmetal on account of the plunger `disk 28. The products of combustionpass out through the pi 'e 41 which serves as a sort of flue. When it 1sdesired to force the metal into the die, all. that is necessary is toclose the valve tostop the flow of the mixture and operate the valve 43Yso as to close the exhaust pipe 41 and turn in lthe compressed airthrough the pipe 42 and pipe 41. The air is under a rather high state ofcompression and it rushes into the chamber surrounding the crucible andover the tube in the crucible above the plunger disk and suddenly andeffectively forces the disk down and thus forces the 4metal up throughthe tube 17 into the die.

The arrangement of the pipes 41 and 42 andvalve 43 is not necessary, butdone for convenience. The advantage of the arrangement of the tubes 41and 42 and valve 43 isthat only the heated gases fromthe pipe A41 wouldreturn into the outer chamber and upper end of the crucible and the coolcompressed air would not reach said members and tend to cool them. Asthey are arranged in the drawings, the compressed air forces'theproducts of combustion which are held -in the pipe 41, back into theoven chamber and crucible, but with the'same degree of pressure as thecompressed air possesses. That does no harm to the metal in thecrucible, however. All that is necessary is that there be some exhaustpipe leading from the oven chamber and also a means for turningcompressed air or the like into said chamber. It is immaterial how thisis done, whether exactly as shown or otherwise.

.The compressed air tube 42 is connected with the exhaust tube 41remotely from the outer chamber 10 so that the capacity of the portionof said exhaust tube 41 between its connection with the tube 42 and theouter .chamber will at least be equal to the un occupied space in theouter chamber l0 and the crucible 27. With this construction,

Valve 43,it will force the warm and inert gases in the tube 41 back intothe unoccupied portion of the outer chamber 10 and the crucible so thatthe air will not enter the chamber 10. The pipe 31 has a checkvalve 44in it which will close umder the `in fluence of the extreme backpressure caused when the compressed air is turned on through the pipe42. With this arrangement the continuous operation of the apparatus ispossible and only one valve 43 needs to be operated after the device isunder way.

'Ihe outlet pipe or nozzle 17 is readily re'y movable and, therefore,can be inserted, after the metal has become heated, into the crucibleand through theplun er plate'28.. This enables the tube 17 to be iftedout of the crucible while casting and then said metal can be heatedoutside and introduced into the crucible highly heated and the castingoperation .be commenced at once. When the nozzle 17, however, is thusremoved, since it is secured to the top 15, another lid shouldpreferably be placed upon the outer chamber while the casting operationis in progress, to 4keep the metal hot until time begin the castingoperation.

I- claim as my invention:

1. A die casting machine including a crucible, a conduit from the lowerpart thereof through which the metal may be forced to a die, means forsupplying heat to the crucible, and means for applying products ofcombustion under pressure upon the metal in the crucible for forcing the-same out through said tube.

2. -A die `casting machine including a crucible, an oven forming achamber surrounding said crucible and in communication with the upperpart thereof, a conduit from the lower part of the crucible throughwhich the metal may be forced to a die, means for introducing heat intothe oven chamber, and means for compressing the products'of combustioninto said oven chamber and crucible for forcing out the metal during thecasting operation.

3. A die casting machine including a crucible with an opening in theupper end, an oven surrounding said crucible leaving a chamber betweenthe crucible and the oven in communication with the upper part of iooconnected with the exhaust tube, and a valve at the connection betweensaid tubes for turning the compressed air into the exhaust tube andforcing the products of combustion backward into the crucible underpressure during the die casting operation.

5. A die casting machine including a crucible, a conduit -leading fromthe lower part thereof through which molten metal may be forced to adie, an oven forming a chamber surrounding the crucible, Valvecontrolled means` for introducing heat into the oven chamber, an exhausttube leading` from the oven chamber, a compressed air tube connectedwith the exhaust tube' away from the oven so that the capacity 0f theexhaust tube between the compressed air tube and the oven will exceedthe unoccupied space in the crucible and oven chamber, and a valve atthe connection between said tubes for turning the compressed air intothe exhaust tube and forcing the products of combustion backward intothe crucible under pressure during the die casting operation.

6. A die casting machine including a crucible open at its upper end withan outlet for the molten metal, a plunger plate adapted to tit snuglybut loosely into said crucible upon the molten metal, an outer chamberinclosing said crucible, a fuel supply tube entering said outer chamberat one side of the crucible, an exhaust tube'leading from said outerchamber at the other side of the crucible, a compressed air pipe leadingto said exhaust tube, and a Valve for simultaneously opening the exhausttube and closing the compressed air tube'when in one position and forclosing the exhaust tube and opening the compressed air tube when in theother position.

v7. A die casting machine including a crucible o pen at its upper end,an oven surrounding the same, a plunger plate adapted to lie upon themetal in the crucible and having an opening therethrough, a removabletube insertible loosely through said plunger plate into the crucible,means for securing a die at the outer end of the tube, and means forintroducing air under pressure into said oven and crucible.

In wit-ness whereof, l havehereunto affixed my signature in the-presenceof the witnesses herein named. f

LAYTON M. PARKHURST. Witnesses:

Gr. H. BOINK,

E. H. MAYO.

